ASSESSING QUALITY OF AN ESSENTIAL OIL 241 general characteristics and condition, and may be illustrated by, t'or ex- ample, cassia oil and eucalyptus oil. In the case of cassia oil lead is frequently present, sometimes up to 400 parts per million or even higher, derived from the leaden containers in which the oil is imported from China. This lead content is of no conse- quence if the oil is to be employed for the production of cinnamic aidehyde, but would cause the oil to be rejected if required for pharmaceutical pur- poses where a stringent lead limit is imposed. Similar remarks apply, of course, to aniseed oil from the same source. Eucalyptus oils are commonly designated according to their cineole content, and if cineole manufacture were the objective then preference would be accorded to the oil of highest cineole content. On the other hand, the secondary constituents associated with a 70/75% cineole-con- raining oil derived from, for example, Eucalyptus australiana, might render the latter much more acceptable as a flavouring ingredient in a toothpaste than oil of 80/85% cineole content from other species of Eucalyptus. The steps to be taken in assessing the quality of an essential oil may be divided into: (a) objective tests to ascertain its general characteristics, and (b) subjective tests to determine whether it is the most suitable oil for a particular purpose. The analyst is primarily concerned with objective tests, and when satis- fied with the results obtained by analysis the subjective tests follow. No other sequence is permissible. Objective tests should be carried out by standard methods and the re- sults compared with data in the literature. The objective tests in question include the determination of physical constants, solubilities, and assay of characteristic groups by methods of proved reliability. Notes should be made of the general condition of the sample in so far as freedom from ex- traneous water, dirt, etc., are concerned, and examination of the non- volatile residue obtained by evaporation on the steam bath frequently yields valuable int'ormation in regard to freedom from auto-oxidation, no- tably in the case of citrus oils. Reliable assay methods are given in such works as the British Pharmacopoeia and Codex, or in the new British Standard No. 2073: 1953, "Methods of Testing Essential Oils," the latter being specially recommended for your attention. Many other assay pro- cedures of a high degree of reliability are given in such works as those of Parry, "The Chemistry of Essential Oils and Artificial Perfumes" (1922) (London: Scott Greenwood & Son, Vol. II) Gildermeister & Hoffmann, "Die J•therische (Sle," 3rd edition, 1928 (Miltitz, Schimmel & Co. A.G., Vol. I) and Guenther, "The Essential Oils" (1948) (New York: D. Van Nostrand & Co., Inc., Vol. I), while in the future considerable develop-

242 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ments will undoubtedly take place in the application of spectrophotometric and chromatographic methods to essential oil analysis. Only when the analyst is absolutely satisfied of the authenticity of the sample under examination should he be inclined to pass an "abnormal" oil for submission to subjective tests. Oils from sources of supply of new geographical origin come into this category, as well as those produced by the employment of modern distillation units in place of "peasant" stills. Brazilian rosewood, sassafras, and dementholised mint oils may be cited as important newcomers to the essential oil markets in recent years, while the controversy over otto of rose in the years immediately before the War is an excellent example of the influence of equipment on the character- istics of an essential oil. Guenther, op. cit., Vol. V, p. 3, et seg., gives an ad- mirable survey of the otto of rose question. Subjective tests on the odour, and, where necessary, flavour, of the essen- tial oil then follow, comparison being made with standard samples kept under proper conditions, followed by trial formulation in which the new oil is incorporated in place of the previously accepted delivery. Standard samples should be kept in small well-filled amber glass bottles, preferably closed with glass stoppers, or alternatively tinfoil-wrapped corks, in a dark cupboard at a uniformly cool temperature. Under such conditions dete- rioration of sensitive oils, such as those from citrus fruits, is likely to be in- appreciable over many months. LIPSTICKS--THEIR FORMULATION, MANUFACTURE, AND ANALYSIS* By A. L. FISHBACH Oxzyn Company, H/est Trenton, N. ]. HF. RE A•F. WWO lipstick formulas--one a "creamy" and one a "high stain." The castor oil is used as the main vehicle for the color and as a partial solvent for the halogenated fluorescein termed "bromo acids." The isopropyl myristate acts to break the viscosity of the castor oil and allow better contact with the lip. The lanolin is used for its emollient properties and for a degree oftackiness and drag. The wax phase is balanced to utilize * Presented at the May 14, 1954, Meeting, New York City.